Heap-based buffer overflow in the cpSeparateBufToContigBuf function in tiffcp.c in LibTIFF 3.9.3, 3.9.4, 3.9.5, 3.9.6, 3.9.7, 4.0.0beta7, 4.0.0alpha4, 4.0.0alpha5, 4.0.0alpha6, 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.0.4, 4.0.4beta, 4.0.5, 4.0.6, 4.0.7, 4.0.8 and 4.0.9 allows remote attackers to cause a denial of service (crash) or possibly have unspecified other impact via a crafted TIFF file.
https://access.redhat.com/errata/RHSA-2019:2053
https://access.redhat.com/errata/RHSA-2019:3419
https://github.com/Hack-Me/Pocs_for_Multi_Versions/tree/main/CVE-2018-12900
https://lists.debian.org/debian-lts-announce/2019/11/msg00027.html
https://usn.ubuntu.com/3906-1/